After a vote to return Mrs Deeming to the party room, a spill motion was raised against Mr Pesutto, the man who had led the campaign to remove her from the party earlier in 2024.
Mr Pesutto opted not to run and Mr Battin was elected above Mornington MP Chris Crewther, while opposition financial spokeswoman Jess Wilson's tilt at the top job failed to pass the first round of voting.
"We now have an obligation to move forward," Mr Battin said after the vote.
"I'm very thankful for the support I've got from my colleagues in the party room today to ensure that we could come out united and get on message with the message we need to have. We know Victorians are hurting."
Mr Battin nominated cost of living, crime, budget repair and roads as issues he would focus on over the next 700 days until the state election in November 2026.
Following the vote, Mr Pesutto congratulated Mr Battin on his ascension as leader.
"I wake up every day and I'm very honoured and privileged to serve the people of Hawthorn," the outgoing leader said.
John Pesutto chose not to contest the leadership, stepping aside from the role. (Joel Carrett/AAP PHOTOS)
Former tennis player Sam Groth was elected unopposed as deputy leader, while David Davis has been elevated to leader of the upper house, with Evan Mulholland retaining his deputy upper house leader role.
Mr Groth appeared to spark the row earlier in December, when he resigned to the back bench after Mr Pesutto refused to step down as leader following his defamation battle loss to Ms Deeming.
A Federal Court judge found Mr Pesutto had defamed Mrs Deeming by implying she was associated with Nazis who gatecrashed a controversial Melbourne rally she attended and ordered he pay her $315,000 and costs.
Before the vote, former party leader Michael O'Brien underscored the need for unity in the ranks.
"Unless we can win and hold government, then we can't enhance the freedom, prosperity and security of Victorians or Australians," Mr O'Brien said as he entered Parliament House.
"So we just need to knuckle down, get behind whatever decision is made today and win the next election for Victoria."
Independent MP Moira Deeming has been welcomed back into the Victorian Liberal Party. (Joel Carrett/AAP PHOTOS)
Ms Wilson had announced her candidacy after a deal to become Mr Battin's deputy came off the table.
"The best way forward to defeat Jacinta Allan and Labor was with a unified leadership ticket," Ms Wilson said.
"Unfortunately, it has been made clear to me that a unity ticket is no longer on the table."
It was the second time the party voted on whether to return Mrs Deeming, the first was rejected after Mr Pesutto cast the tie-breaking vote in an issue that split the party down the middle.
Mr Battin will take the reins less than two years before a pivotal state election at which the Labor government will seek a rare fourth term.
